WO2019181805A1

WO2019181805A1 - Fixing member, fixing device, and electrophotographic image-forming apparatus

Info

Publication number: WO2019181805A1
Application number: PCT/JP2019/010950
Authority: WO
Inventors: 陽平宮内; 康晴能登屋; 吉村　公博
Original assignee: キヤノン株式会社
Priority date: 2018-03-22
Filing date: 2019-03-15
Publication date: 2019-09-26
Also published as: EP3770689B1; EP3770689A1; EP3770689A4

Abstract

Provided is a fixing member for electrophotography, the fixing member exhibiting excellent toner releasability even after long-term use. The fixing member comprises a base layer, an elastic layer, and a surface layer in this order, wherein the elastic layer contains a silicone rubber, and the surface layer consists of a single layer, and contains a fluoro resin and a fluoro oil having a perfluoropolyether structure. When treatment (i) is performed on a measurement sample taken from the surface layer, the mass P11 of a deposit containing the fluoro oil and attached to a detection surface of a QCM sensor is 1.0×10² to 1.0×10⁴ ng per unit area of the detection surface, and when treatment (ii) is performed on the measurement sample, the mass P12 of a deposit containing the fluoro oil and attached to the detection surface of the QCM sensor is 0.5×P11 to 1.2×P11 per unit area of the detection surface.

Description

Fixing member, fixing device, and electrophotographic image forming apparatus

The present invention relates to a fixing member, a fixing device, and an electrophotographic image forming apparatus.

In a fixing device used in an electrophotographic image forming apparatus (hereinafter also referred to as “image forming apparatus”) such as a copying machine or a laser printer, a pair of heated rollers and rollers, a film and rollers, a belt and rollers, a belt and belts A rotating body such as is pressed. Then, a recording medium such as paper holding an image formed with unfixed toner is introduced into a pressure contact portion (hereinafter referred to as a “fixing nip portion”) formed between the rotating bodies, and the unfixed toner is removed. By heating and melting, the image is fixed on the recording medium. A rotating body that contacts an unfixed toner image on a recording medium is called a fixing member, and is called a fixing roller, a fixing film, or a fixing belt depending on the form.
In a fixing member for electrophotography, a fluororesin, specifically, a surface layer (hereinafter referred to as “surface layer”) that constitutes an outer surface in contact with the toner is used to suppress adhesion of the toner. For example, a surface layer containing a copolymer of tetrafluoroethylene (—C ₂ F ₄ —) and perfluoroalkyl vinyl ether (—CF ₂ —CF (ORf) —) (hereinafter also referred to as “PFA”). Sometimes used. Here, “Rf” represents a perfluoroalkyl group.
In recent years, paper media used for the formation of electrophotographic images have been diversified, and for example, it has been required to cope with thin paper having a basis weight of 52 g / m ² . However, since such a thin paper has low rigidity, in the conventional fixing member, the molten toner at the time of thermal fixing may adhere to the surface of the surface layer, and the thin paper may wrap around the fixing member. In order to stably form an electrophotographic image on thin paper, the surface of the fixing member needs to have higher toner releasability.
Here, in Patent Document 1, a layer containing a fluoropolymer such as PFA having a perfluoropolyether (hereinafter also referred to as “PFPE”) structure or a compound having a perfluoroalkyl group covalently bonded thereto is provided on the outermost surface. A liquid repellent film having a liquid repellent film and a fixing member having the liquid repellent film are disclosed.

Japanese Patent Laid-Open No. 2018-22056

According to studies by the present inventors, it has been confirmed that the fixing member according to Patent Document 1 has excellent toner releasability. Therefore, the present inventors have studied a fixing member in which a liquid repellent film according to Patent Document 1 is provided as a surface layer on an elastic layer containing silicone rubber. However, as a result of long-term use, the toner releasability on the outer surface of the fixing member is lowered, and when an electrophotographic image is formed on the thin paper as described above, the thin paper may be wound around the fixing member. there were.
One aspect of the present invention is directed to providing a fixing member capable of maintaining high toner releasability over a long period of time. Another aspect of the present invention is directed to providing a fixing device that contributes to long-term stable formation of high-quality electrophotographic images. Furthermore, another aspect of the present invention is directed to providing an electrophotographic image forming apparatus capable of stably forming a high-quality electrophotographic image over a long period of time.

According to one aspect of the present invention, there is provided a fixing member for electrophotography having a base layer, an elastic layer, and a surface layer on the elastic layer in this order in the thickness direction,
The elastic layer comprises silicone rubber;
The surface layer consists of a single layer;
The surface layer includes a fluororesin and a fluoro oil having a perfluoropolyether structure, and the fixing member is provided with a fixing member that satisfies the requirements (i) and (ii):
(I) For a measurement sample including the entire thickness portion of the surface layer collected from the fixing member, after cleaning a predetermined position on the first surface opposite to the side facing the base layer, A unit area of the detection surface when a process of pressing the detection surface of the quartz crystal microbalance (QCM) sensor at a temperature of 180 ° C. for 50 msec with respect to the position is performed. The mass P11 of the deposit containing the fluorine oil having a perfluoropolyether structure attached to (1 cm ² ) is 1.0 × 10 ² ng or more and 1.0 × 10 ⁴ ng or less;
(Ii) For the measurement sample subjected to the treatment specified in the requirement (i), after cleaning the position, the sample is placed in an environment at a temperature of 180 ° C. for 120 seconds, and then a quartz crystal microbalance (QCM) is placed at the position. ) A perfluoropolyether structure adhering to the unit area (1 cm ² ) of the detection surface when the detection surface of the sensor is pressed at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. The mass P12 of the deposit containing fluorine oil is 0.5 × P11 or more and 1.2 × P11 or less.

According to another aspect of the present invention, there is provided a fixing member for electrophotography having a base layer, an elastic layer, and a surface layer on the elastic layer in this order in the thickness direction,
The elastic layer comprises silicone rubber;
The surface layer consists of a single layer;
The surface layer was opposed to the base layer with respect to a measurement sample including a fluororesin and a fluoro oil having a perfluoropolyether structure and including the entire thickness portion of the surface layer collected from the fixing member. When the detection surface of the quartz crystal microbalance (QCM) sensor is pressed at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec against the first surface opposite to the first surface, the detection surface P11 (ng) is the mass of the deposit containing fluorine oil having a perfluoropolyether structure attached to the unit area (1 cm ² ) of
With respect to the second surface of the measurement sample facing the base layer, the detection surface of the quartz crystal microbalance (QCM) sensor is set to a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. When the mass of the deposit containing fluorine oil having a perfluoropolyether structure that adheres to the unit area (1 cm ² ) of the detection surface when pressed is P21 (ng), the fixing member satisfying P21> P11 is obtained. Provided.
Furthermore, according to another aspect of the present invention, there is provided a fixing device including the above-described fixing member and a heating unit for the fixing member. Furthermore, according to another aspect of the present invention, there is provided an electrophotographic image forming apparatus provided with the above fixing device.

According to one aspect of the present invention, it is possible to obtain a fixing member that can maintain excellent toner releasability even during long-term use. According to another aspect of the present invention, a fixing device that contributes to stable formation of a high-quality electrophotographic image can be obtained. Furthermore, according to another aspect of the present invention, an electrophotographic image forming apparatus that can stably form a high-quality electrophotographic image over a long period of time can be obtained.

3 is a surface observation image of a fixing member described in Example 1. FIG. 6 is a surface observation image of a fixing member described in Comparative Example 4. FIG. 3 is a schematic cross-sectional view of a fixing belt which is an example of the present invention. FIG. 3 is a schematic cross-sectional view of a fixing roller that is an example of the present invention. 1 is a schematic cross-sectional view of a fixing device using a fixing belt according to the present invention. 1 is a schematic cross-sectional view of a fixing device using a fixing roller according to the present invention. 1 is a schematic cross-sectional schematic view showing one embodiment of an electrophotographic image forming apparatus of the present invention. It is a cross-sectional schematic diagram of the fixing member according to the present invention. It is a schematic diagram of the fluorine oil amount of the surface layer of the fixing member according to the present invention.

According to studies by the present inventors, it has been confirmed that the fixing member according to Patent Document 1 has excellent toner releasability. Therefore, the present inventors have studied a fixing member in which the liquid repellent film according to Patent Document 1 is provided as a surface layer on an elastic layer containing silicone rubber. However, as a result of long-term use, the toner releasability on the outer surface of the fixing member is lowered, and when an electrophotographic image is formed on the thin paper as described above, the thin paper may be wound around the fixing member. there were.
Such a decrease in toner releasability with time is considered to be due to the surface layer being worn by repeated deformation of the surface layer accompanying deformation of the elastic layer in the fixing nip portion. This is presumably because a compound having a perfluoropolyether structure or a perfluoroalkyl chain contributing to an improvement in toner releasability is lost from the outer surface of the fixing member.
The inventors of the present invention have made studies for the purpose of obtaining a fixing member capable of maintaining excellent toner releasability even after long-term use. As a result, it has been found that the fixing member according to the above-described aspect can satisfactorily achieve such an object. Hereinafter, the fixing member according to each aspect will be described in detail.

The fixing member according to one embodiment of the present invention includes a base layer, an elastic layer, and a surface layer on the elastic layer in this order in the thickness direction. The elastic layer includes silicone rubber, and the surface layer is formed of a single layer. The surface layer includes a fluororesin and a fluoro oil having a perfluoropolyether structure (hereinafter also simply referred to as “fluoro oil”). And including.
The fixing member satisfies the following requirements (i) and (ii).
Requirement (i): For a measurement sample including the entire thickness portion of the surface layer collected from the fixing member, a predetermined position on the first surface opposite to the side facing the base layer is cleaned. . After that, a process of pressing the detection surface of the quartz crystal microbalance (QCM) sensor with a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec is performed on the position. At this time, the mass P11 of the deposit containing fluorine oil that adheres to the unit area (1 cm ² ) of the detection surface is 1.0 × 10 ² ng or more and 1.0 × 10 ⁴ ng or less.
Requirement (ii): The measurement sample subjected to the treatment specified in the above requirement (i) is placed in an environment at a temperature of 180 ° C. for 120 seconds after the position is cleaned. Next, a process of pressing the detection surface of the QCM sensor at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec is performed at the position. At this time, the mass P12 of the deposit containing fluorine oil adhering to the unit area (1 cm ² ) of the detection surface is 0.5 × P11 or more and 1.2 × P11 or less.

The treatment defined in the requirement (i) is performed on the first surface (hereinafter also referred to as “outer surface”) of the fluorine oil contained in the surface layer opposite to the side of the surface layer facing the base layer. It is positioned as a process to be transferred. That is, the pressing conditions (pressure, temperature, pressurization time) on the outer surface in the treatment specified in (i) above are the outer surface of the surface layer of the fixing member in the fixing nip during thermal fixing in the electrophotographic image forming process. Is set to correspond to the conditions applied to
Further, the amount of fluorine oil present on the outer surface of the fixing member can be measured using a crystal resonator. The crystal resonator has a sensitivity capable of measuring a mass on the order of nanograms. A crystal resonator has a structure in which both surfaces of a crystal plate of crystal are sandwiched between metal electrodes. When an alternating electric field is applied to the metal electrodes on both sides, the crystal resonator vibrates at a constant frequency (resonance frequency) due to a reverse voltage drop of the crystal. When a minute amount of material adheres to the metal electrode, the resonance frequency decreases in proportion to the amount of adhesion. By utilizing this phenomenon, the crystal resonator can be used as a microbalance.
The amount of change in the frequency of the crystal resonator and the mass of the adhering substance on the metal electrode are in accordance with the following Sauerbrey formula (formula (a)).

(In formula (a), ΔF: frequency change, Δm: mass change amount, F ₀ : fundamental frequency, ρ _Q : crystal density, μ _Q : shear stress of crystal, A: electrode area).
This measuring method is also referred to as a quartz crystal microbalance (QCM) method.

Furthermore, “cleaning” according to the above requirement (i) means that a non-woven fabric soaked with ethanol is placed at the position, and a load of 20 kPa is applied on the non-woven fabric and the position is reciprocated 10 times. Subsequently, toluene is impregnated with the nonwoven fabric placed at this position, and a load of 20 kPa is applied on the nonwoven fabric to reciprocate the position 10 times. Thereby, the fluorine oil which exists on an outer surface is removed mechanically. On the other hand, since ethanol and toluene do not dissolve PFPE, PFPE present in the surface layer is not eluted.
Therefore, the above requirement (i) is such that the amount of the fluorine oil that has existed in the surface layer by the pressing treatment specified in the requirement (i) oozes out to the first surface of the surface layer is 1.0. It means that it is not less than × 10 ² ng and not more than 1.0 × 10 ⁴ ng. By setting P11 within the above numerical range, it is possible to significantly suppress toner adhesion to the outer surface of the fixing member during thermal fixing. As a result, it is possible to prevent occurrence of toner offset at the time of heat fixing, and it is also possible to prevent occurrence of offset due to toner cohesive failure due to the viscosity of the fluorine oil. P11 is more preferably 1.0 × 10 ² ng or more and 5.0 × 10 ³ ng or less.
As a method for preparing a measurement sample including the entire thickness portion of the surface layer from the fixing member, for example, when the fixing member has a configuration in which an elastic layer and a surface layer are sequentially laminated on a base layer, the elastic sample is elastic. Examples include a method of cutting out a laminate of a layer and a surface layer and removing the elastic layer from the laminate. The elastic layer can be removed from the laminate by peeling the surface layer from the interface with the elastic layer with a knife, or by dissolving the resin component in the elastic layer without dissolving the fluororesin in the surface layer. And a method of dissolving and removing only the elastic layer using a simple solvent. For example, when the elastic layer contains silicone rubber, only the elastic layer can be dissolved and removed from the laminate by using a resin solubilizer (trade name: esolve 21RS, manufactured by Kaneko Chemical Co., Ltd.).

Next, the treatment according to the above requirement (ii) is the requirement (i) for the measurement sample in which the fluoro oil contained in the surface layer is transferred to the first surface of the surface layer by the treatment according to the requirement (i). The cleaning which removes the fluorine oil which transferred to this 1st surface by the process which concerns on is performed. Next, after being placed in a predetermined environment, it is a process for transferring fluorine oil from the inside of the measurement sample to the first surface.
Here, “cleaning” refers to the same operation as “cleaning” in requirement (i). The fixing member according to this aspect is configured such that when the mass of the adhering material including fluorine oil adhering to the unit area of the detection surface of the QCM sensor when performing the processing according to the requirement (ii) is P12, It is 0.5 times or more and 1.2 times or less of P11. This is because the first surface of the surface layer has an appropriate amount so that excellent toner releasability can be exhibited even after the fluorine oil transferred to the outer surface by the treatment according to the above requirement (i) is removed. It means that the fluorine oil can migrate from the inside of the surface layer to the outside surface.
That is, the fixing member satisfying the requirements (i) and (ii) is supplied with fluorine oil from the inside of the surface layer to the outer surface even if the outer surface fluorine oil is once consumed in one thermal fixing step. High toner releasability can be maintained over a long period of time.
For the pressing process according to the above requirements (i) and (ii), for example, a tack tester (trade name: TAC-1000, manufactured by Resca) can be used. Specifically, a crystal resonator is placed on the stage unit of the testing machine. On the other hand, the measurement sample including the entire thickness portion of the surface layer collected from the fixing member is fixed to the probe of the test machine so that the first surface of the measurement sample faces the crystal resonator. Next, the probe is brought close to the stage portion and the first surface of the measurement sample is pressed against the crystal resonator. The pressing conditions are as follows.
・ Pressure: 0.4 MPa,
・ Pressing time: 50 msec,
・ Push-in constant mode,
・ Pressing and lifting speed: 1.0 mm / sec,
Probe set temperature: 180 ° C.

1. Fixing Member FIGS. 3A and 3B are cross-sectional views showing different aspects of the fixing member according to the present invention. 3A shows a fixing member having an endless belt shape (hereinafter also referred to as “fixing belt 11”), and FIG. 3B shows a roller-shaped fixing member (hereinafter also referred to as “fixing roller 12”).
The fixing member according to FIGS. 3A and 3B includes a base layer 13, an elastic layer 14 that covers the outer surface thereof, and a surface layer that covers the surface of the elastic layer opposite to the side facing the base layer. 15. The surface layer 15 may be bonded to the surface of the elastic layer 14 opposite to the side facing the base layer with an adhesive layer (not shown).
FIG. 7A shows a base layer 13, an elastic layer 14, a surface layer 15, and a first surface (outer surface) 15a opposite to the side facing the base layer of the fixing member according to this embodiment, It is sectional drawing which shows the relationship with the 2nd surface 15b of the side facing a base layer. FIG. 7B shows that, in the surface layer 15, when the mass P11 of the fluorine oil on the first surface 15a is compared with the mass P21 of the fluorine oil on the second surface 15b, P21 is larger than P11.

(1) Base layer As a material of the base layer 13, metals and alloys such as aluminum, iron, stainless steel, and nickel, and heat resistant resins such as polyimide are used.
In the fixing belt 11, a substrate having an endless belt shape may be used as the base layer 13. In this case, examples of the material of the base layer 13 include materials having excellent heat resistance such as nickel, stainless steel, and polyimide. The thickness of the base layer 13 is not particularly limited, but is preferably 20 μm or more and 100 μm or less from the viewpoint of strength, flexibility, and heat capacity, for example.
In the fixing roller 12, for example, a solid or hollow core metal is used as the base layer 13. Examples of the material of the metal core include metals such as aluminum, iron, and stainless steel, and alloys. In the case of using a hollow cored bar, a heat source can be provided inside.
A surface treatment may be applied to the outer surface of the base layer 13 in order to provide adhesion with the elastic layer 14. For the surface treatment, physical treatment such as blast treatment, lapping treatment, and polishing, oxidation treatment, coupling agent treatment, and chemical treatment such as primer treatment can be used singly or in combination.
When the elastic layer 14 containing silicone rubber is provided on the surface of the base layer 13, it is preferable to apply a primer treatment to the surface of the base layer 13 in order to improve the adhesion between the base layer 13 and the elastic layer 14. Examples of the primer used for the primer treatment include a paint in which a coloring agent such as a silane coupling agent, a silicone polymer, a hydrogenated methylsiloxane, an alkoxysilane, a reaction promoting catalyst, or a bengara is appropriately blended and dispersed in an organic solvent. It is done.
The primer can be appropriately selected depending on the material of the base layer 13, the type of the elastic layer 14, or the form of the crosslinking reaction. In particular, when the elastic layer 14 contains a large amount of unsaturated aliphatic groups, a primer containing a hydrosilyl group is preferably used in order to impart adhesiveness by reaction with the unsaturated aliphatic group. When the elastic layer 14 contains many hydrosilyl groups, a primer containing an unsaturated aliphatic group is preferably used. In addition to the above, a primer containing an alkoxy group is also included. A commercially available primer can be used. The primer treatment includes a step of applying this primer to the outer surface of the base layer 13 (an adhesive surface with the elastic layer 14), and drying or baking.

(2) Elastic layer It is preferable that the elastic layer 14 contains silicone rubber having excellent heat resistance. Further, as a raw material for the silicone rubber, an addition curable liquid silicone rubber is preferably used.
The thickness of the elastic layer 14 can be appropriately designed in consideration of the surface hardness of the fixing member and the width of the fixing nip portion to be formed. When the fixing member is the fixing belt 11, the thickness of the elastic layer 14 is preferably 100 μm or more and 500 μm or less, and more preferably 200 μm or more and 400 μm or less.
When the fixing member is the fixing roller 12, the thickness of the elastic layer 14 is preferably 0.1 mm (100 μm) or more and 3.0 mm or less, more preferably 0.3 mm (300 μm) or more and 2.0 mm or less. preferable.
By setting the thickness of the elastic layer 14 within this range, a sufficient width of the fixing nip portion can be secured when the fixing member is incorporated in the fixing device.
In addition, since the elastic layer contains silicone rubber having poor chemical affinity with fluorine oil, the fluorine oil contained in the surface layer is difficult to move to the elastic layer even during long-term use, and is supplied exclusively to the surface of the fixing member. The
The elastic layer 14 may contain a filler. A filler is added in order to control thermal conductivity, heat resistance, and elastic modulus. Specifically, silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), silica (SiO ₂ ), boron nitride (BN), aluminum nitride (AlN), alumina (Al ₂ O ₃ ), iron oxide (Fe ₂ O ₃ ), zinc oxide (ZnO), magnesium oxide (MgO), titanium oxide (TiO ₂ ), copper (Cu), aluminum (Al), silver (Ag), iron (Fe), nickel (Ni), carbon Examples thereof include black (C), carbon fiber (C), and carbon nanotube (C).
Further, the material constituting the elastic layer 14 may be blended with a reaction control agent (inhibitor) called an inhibitor for controlling the reaction start time. As the reaction control agent, known substances such as methyl vinyl tetrasiloxane, acetylene alcohols, siloxane-modified acetylene alcohol, and hydroperoxide are used.

(3) Surface layer The surface layer 15 contains a fluororesin and fluorine oil having a perfluoropolyether (PFPE) structure. The surface layer satisfies the requirements (i) and (ii) described above.
The fixing member satisfying the requirements (i) and (ii) can be achieved, for example, by a surface layer containing a larger amount of fluoro oil on the base layer side than on the outer surface side in the thickness direction of the surface layer.
For example, for the measurement sample including the entire thickness portion of the surface layer collected from the fixing member, the detection surface of the quartz crystal microbalance (QCM) sensor with respect to the second surface on the side facing the base layer Is pressed at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. At this time, when the mass P21 (ng) of the deposit containing fluorine oil having a perfluoropolyether structure that adheres to the unit area (1 cm ² ) of the detection surface, P21 and P11 are represented by the following formula (1). The fixing member showing can satisfy the requirements (i) and (ii).

P21> P11 (1)

Since both the fluororesin and the fluoro oil have low surface free energy, it may be difficult to interact without causing phase separation. However, the present inventors phase-separate the fluoro oil from the fluororesin in the surface layer by bringing the fluoro oil into contact with the outer surface of the surface layer at a temperature near the melting point of the fluororesin in the surface layer. It discovered that it could be made to contain without. Further, when fluorine oil is contained in the surface layer by such a method, the fluorine oil penetrates to the vicinity of the interface with the elastic layer in the surface layer in the thickness direction of the surface layer, and in the vicinity of the interface. The fluorine oil concentration was higher in the surface layer than on the first surface side of the surface layer.
The reason why the concentration of the fluorine oil is high on the side close to the elastic layer of the surface layer is not clear, but is estimated as follows. First, the fluoro oil is brought into contact with the vicinity of the melting point of the fluororesin so that the fluoro oil quickly diffuses in the fluororesin and reaches the vicinity of the interface with the elastic layer. Next, in the process in which the surface layer is cooled from the vicinity of the melting point of the fluororesin to room temperature, molecular shrinkage of the fluororesin in the surface layer occurs, and fluorine oil is released from the first surface side to the first surface of the surface layer. . As a result, the concentration of the fluorine oil in the surface layer is considered to be higher on the interface side with the elastic layer than on the first surface side of the elastic layer.
Then, such a fluorine oil concentration gradient is formed in the surface layer, so that the surface layer functions as a fluorine oil reservoir. Therefore, even if fluorine oil on the first surface of the surface layer is consumed at the time of heat fixing, the fluorine oil of the surface layer is continuously supplied to the first surface due to the principle of material diffusion, and even in long-term use It is considered that the toner releasability on the outer surface of the fixing member is maintained.

Note that the difference in the concentration of fluorine oil on the first surface side in the thickness direction of the surface layer and on the interface side with the elastic layer can be easily confirmed, for example, by measuring by infrared spectroscopy.

For the production of the fixing member according to this aspect, any method can be used as long as the fluorine oil containing the PFPE structure can be contact impregnated at a temperature near the melting point of the fluororesin contained in the surface layer. The surface layer in contact with the fluorine oil may be a surface layer in a fixing member in which a base layer, an elastic layer, and a surface layer are laminated in advance, or a fluororesin tube for the surface layer is prepared and adhered to the elastic layer. You may use the thing of the state which masked the surface of the side. Moreover, as a contact method, it can produce by the dipping method, for example.
Specifically, for example, the surface layer is a copolymer of tetrafluoroethylene (—C ₂ F ₄ —) as a fluororesin and perfluoroalkyl vinyl ether (—CF ₂ —CF (ORf) —) (hereinafter referred to as “fluorocarbon resin”). In the case of including "PFA"), it can be obtained through the following steps a) to c).
Step a) A preliminary fixing member in which a base layer, an elastic layer containing silicone rubber, and a resin layer containing PFA are laminated in this order is attached to a dipping device.
Step b) The preliminary fixing member is immersed in a fluorine oil bath that has been heated in the vicinity of the melting point of PFA (300 ° C. ± 50 ° C.) in advance and left for 5 minutes.
Step c) After removing the preliminary fixing member from the fluoro oil bath, the PFPE adhering to the outer surface of the resin layer is removed and cooled to room temperature.
The temperature of the fluorine oil bath in step b) has a correlation with the amount of fluorine oil impregnated into the resin layer, and the amount of impregnation increases as the temperature increases. The contact time may be several to several tens of minutes. A method for removing an excessive amount of PFPE adhering to the surface is not particularly limited, and examples thereof include a method of cleaning with a fluorine solvent and a method of removing with air.
The method for supplying the fluorine oil to the outer surface of the resin layer is not limited to the dipping method described above. For example, as a method of supplying fluorine oil to the outer surface of the resin layer, a known coating method such as spray coating, roll coating, or beam coating can be used.

<Fluorine resin>
The fluororesin is not particularly limited, and specifically, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), Crystals of polychlorotetrafluoroethylene (PCTFE), tetrafluoroethylene-ethylene copolymer (ETFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), etc. And a non-crystalline fluororesin having a cyclic perfluoropolyether structure. In particular, PFA can be suitably used from the viewpoints of heat resistance, mechanical strength, and workability.
PFA is a copolymer of perfluoroalkyl vinyl ether (hereinafter referred to as “PAVE”) and tetrafluoroethylene (hereinafter referred to as “TFE”), and PAVE is a perfluoromethyl vinyl ether (CF ₂ ═CF— O—CF ₃ ), perfluoroethyl vinyl ether (CF ₂ ═CF—O—CF ₂ CF ₃ ) and perfluoropropyl vinyl ether (CF ₂ ═CF—O—CF ₂ CF ₂ CF ₃ ).

A commercially available product can be used as the PFA, and specific examples are given below.
"451HP-J", "959HP-Plus", "350-J", "950HP-Plus" (both trade names, manufactured by Mitsui-Kemers Fluoro Products);
"P-66P", "P-66PT", "P-802UP" (all trade names, manufactured by AGC);
"AP-230", "AP-231SH", etc. (both trade names, manufactured by Daikin Industries); "6502N" (trade name, manufactured by 3M).
Regarding PFA, the amount of impregnation of PFPE has a correlation with the PAVE content ratio in PFA, and the impregnation amount increases as the PAVE content ratio increases. This is considered to be because fluorine oil tends to interact with the amorphous part of PFA having high molecular mobility. The content ratio of PAVE in PFA is preferably 1 mol% or more and 5 mol% or less in the molecular chain, and particularly preferably 3 mol% or more and 5 mol% or less. The PAVE content ratio can be calculated by measuring ¹⁹ F NMR.
Among the above-mentioned commercially available PFA, “451HP-J”, “959HP-Plus”, “950HP-Plus”, “P-66P”, “P-66PT”, “AP-231SH” “6502N”, “AW-” The PAVE content ratio of “5000 L” is shown in Table 1.

<Fluorine oil>
Fluorine oil has a perfluoropolyether structure, and specific examples include perfluoropolyether (PFPE) having a structure represented by the following structural formula (1). Among such PFPEs, those that are oily at the melting point of the fluororesin are preferably used.

(In Structural Formula (1), a, b, c, d, e, and f are each independently 0 or a positive integer, satisfying 1 ≦ a + b + c + d + e + f ≦ 600, and a, b, c, and d At least one is a positive integer.)
Further, the order of existence of each repeating unit in the structural formula (1) is not limited to the order described in the structural formula (1). Further, each repeating unit may be present at a plurality of positions in the PFPE represented by the structural formula (1). That is, the PFPE represented by the structural formula (1) may be a block copolymer or a random copolymer.
The molecular weight of PFPE is preferably 5,000 or more, particularly 7,000 or more, as the number average molecular weight, from the viewpoint of heat resistance. Further, from the viewpoint of easy interaction with the fluororesin at the time of contact, it is preferably 100,000 or less, particularly preferably 30,000 or less. The PFPE having the above molecular weight is less than 1% in weight loss even when heated in air at 350 ° C. for 30 minutes, and there is very little thermal decomposition even at a temperature near the melting point of the fluororesin.
The content of PFPE in the surface layer is preferably 1.0% by mass or more and 25% by mass or less with respect to the total amount of the fluororesin and PFPE. If it is less than 1% by mass, the releasability of the surface layer cannot be improved, and if it is more than 25% by mass, excess PFPE is easily supplied to the nip portion, and toner offset tends to occur.

Specific examples of PFPE having a structure included in the structure represented by the structural formula (1) are given below. As an example, there may be mentioned those having at least one chemical structure selected from the group consisting of structural formulas (2) to (4).
PFPE having the structure represented by the structural formula (2) (for example, “Demnum-S200”, “Demnum-S100” (both trade names; manufactured by Daikin Industries, Ltd., referred to as “Demnum type”)):

(In Structural Formula (2), n represents an integer of 1 or more.)
PFPE having a structure represented by the structural formula (3) (for example, “Krytox GPL107”, “Krytox GPL106”, “Krytox 143AD”, “Krytox VPF16256”, “Krytox XHT-500”, “Krytox XHT-750” , “Krytox XHT-1000” (all trade names; manufactured by Chemers Inc., referred to as “Krytox type”)):

(In Structural Formula (3), n represents an integer of 1 or more.)
PFA represented by structural formula (4) (for example, “Fomblin M60”, “Fomblin M30” (both trade names, manufactured by Solvay, Inc., referred to as “Fomblin type”)):

(In Structural Formula (4), m and n each independently represents an integer of 1 or more).
The amount of perfluoropolyether impregnation is correlated with the solubility parameter. Specifically, it can be controlled by the SP value difference (ΔHSP value) between the fluororesin and the perfluoropolyether calculated from the Hansen solubility parameter (HSP value). When the ΔHSP value between the two components is small, both are easily dissolved, that is, more easily mixed and the amount of impregnation increases.
The ΔHSP value can be calculated using 3rd Edition 3.1.14 of calculation software “HSPiP” with a database developed and sold by the Hansen Group. When the present inventors calculated ΔHSP values of PFA and PFPE, Krytox type = 2.8, demnum type = 3.6, Fomblin type = 5.4, and the affinity with PFA differs depending on the chemical structure of PFPE. I understood that. That is, when PFPE of each chemical structure is brought into contact with PFA under the same conditions, the Krytox type is most easily compatible with PFA.
The thickness of the surface layer 15 is 3.0 μm or more, more preferably 5.0 μm or more, and particularly preferably 10 μm or more, from the viewpoint of suppressing surface abrasion when the fixing member is used. Further, from the viewpoint of suppressing a decrease in thermal conductivity in the thickness direction as a fixing member, it is preferably 50 μm or less, particularly preferably 40 μm or less.

2. Thermal Fixing Device A thermal fixing device according to an aspect of the present invention includes a heating rotator, and a pressing rotator disposed so as to form a fixing nip portion with the heating rotator. . Examples of the combination of the heating rotator and the pressure rotator include, for example, a heating roller and an elastic pressure roller disposed opposite to the heating roller, and a heating film and the heating film. Mention may be made of elastic pressure rollers. As another example of the combination of the rotating body for heating and the rotating body for pressurization, the heating belt and the elastic pressure roller disposed in contact with the heating belt, and the heating belt and the heating belt are disposed in contact with the heating belt. Examples thereof include an elastic pressure belt.

(1) Fixing Device Using Fixing Belt FIG. 4 is a cross-sectional view in a direction perpendicular to the longitudinal direction of a thermal fixing device including a fixing belt 11 for heating and an elastic pressure roller 19.
The fixing belt 11 is a fixing belt according to one embodiment of the present invention. The fixing belt 11 is loosely fitted on the belt guide member 16. The pressurizing rigid stay 18 is inserted inside the belt guide member 16. The belt guide member 16 is made of, for example, a resin having heat resistance and heat insulation.
A ceramic heater 17 serving as a heat source is provided at a position where the belt guide member 16 and the inner surface of the fixing belt 11 are in contact with each other. The ceramic heater 17 is fitted in and fixed to a groove provided along the longitudinal direction of the belt guide member 16. The ceramic heater 17 is energized by means (not shown) to generate heat.
The elastic pressure roller 19 is provided with an elastic layer 19b containing a cured silicone rubber, for example, on the peripheral surface of a stainless steel core 19a. Moreover, the surface layer 19c containing a fluororesin is provided on the surrounding surface of the elastic layer 19b. The thickness of the surface layer 19c is, for example, 50 μm.
A pressing force is applied to the pressurizing rigid stay 18 by contracting a pressurizing spring (not shown) between both ends of the pressurizing rigid stay 18 and a spring receiving member (not shown) on the apparatus chassis side. ing. As a result, the lower surface of the ceramic heater 17 disposed on the lower surface of the belt guide member 16 and the upper surface of the elastic pressure roller 19 are pressed against each other with the fixing belt 11 interposed therebetween to form a predetermined fixing nip portion N. That is, the lower surface of the ceramic heater 17 is disposed in contact with the inner peripheral surface of the fixing belt 11.
The recording medium P, which is an object to be heated, on which an image is formed with the unfixed toner G in the fixing nip portion N is nipped and conveyed at a conveyance speed V. As a result, the toner image is heated and pressurized. As a result, the toner image is melted and mixed, and then cooled to fix the toner image on the recording medium P.

(2) Thermal Fixing Device Using Fixing Roller FIG. 5 shows a fixing roller 12 for heating, an elastic pressure roller 19 disposed opposite to the fixing roller 12, and a heater 20 as a heating means for the fixing roller 12. 2 is a cross-sectional view in a direction orthogonal to the longitudinal direction of a thermal fixing device including
The fixing roller 12 is a fixing roller according to an aspect of the present invention. In the fixing roller 12, an elastic layer 14 is formed on the outer peripheral surface of a hollow core metal as a base layer 13, and a surface layer 15 is formed on the outer side thereof.
The fixing roller 12 and the elastic pressure roller 19 are pressed against each other by a pressing unit (not shown) to form a fixing nip portion N.
Inside the fixing roller 12 and the elastic pressure roller 19, a heater 20 is installed as a heat source for supplying heat necessary for melting the unfixed toner G. As the heater 20, a halogen heater is generally used. In some cases, a plurality of halogen heaters are installed inside according to the size of the recording medium P being conveyed.
A rotation force is applied to the fixing roller 12 and the elastic pressure roller 19 through the end portions of the base layer (core metal) 13 and the core metal 19a by means not shown, and the moving speed of the surface of the fixing roller 12 is the conveyance speed V of the recording medium P. The rotation is controlled so that the speed is substantially constant. At this time, the rotational force is applied to either the fixing roller 12 or the elastic pressure roller 19 having elasticity, and the other may be rotated by being driven, or the rotational force may be applied to both. .
The recording medium P to be heated, on which an image is formed with the unfixed toner G, is nipped and conveyed to the fixing nip portion N of the fixing device formed in this way. As a result, the toner image is heated and pressurized. As a result, the toner image is melted and mixed, and then cooled to fix the toner image on the recording medium P.

3. Image Forming Apparatus As the image forming apparatus, there are a multifunction machine using an electrophotographic method, a copy machine, a fax machine, a printer, and the like. Here, a color laser printer is taken as an example, and the overall configuration of the image forming apparatus will be outlined.
FIG. 6 is a schematic cross-sectional view of a laser printer 40 according to one embodiment of the present invention. The laser printer 40 shown in FIG. 6 includes an electrophotographic photosensitive drum 39 (hereinafter referred to as “photosensitive member”) that rotates at a constant speed for each color of yellow (Y), magenta (M), cyan (C), and black (K). And an image forming unit having a drum 39 "). The image forming unit further includes an intermediate transfer member 38 that holds the color image that has been developed and transferred in a multiple manner and further transfers the color image to the recording medium P fed from the feeding unit.
The photosensitive drum 39 (39Y, 39M, 39C, 39K) is rotationally driven counterclockwise as shown in FIG. 6 by driving means (not shown).
A charging device 21 (21Y, 21M, 21C, 21K) for uniformly charging the surface of the photosensitive drum 39 in order according to the rotation direction, and a laser beam are irradiated on the periphery of the photosensitive drum 39 based on image information. , A scanner unit 22 (22Y, 22M, 22C, 22K) for forming an electrostatic latent image on the photosensitive drum 39, and a developing unit 23 (23Y, 23M, for developing a toner image by attaching toner to the electrostatic latent image. 23C, 23K), a primary transfer roller 24 (24Y, 24M, 24C, 24K) for transferring the toner image on the photosensitive drum 39 to the intermediate transfer member 38 at the primary transfer portion T1, and remains on the surface of the photosensitive drum 39 after transfer. A cleaning unit 25 (25Y, 25M, 25C, 25K) having a cleaning blade for removing residual transfer toner is disposed. .

When forming an image, a belt-like intermediate transfer member 38 stretched around

rollers

26, 27, and 28 rotates and each color toner image formed on each photosensitive drum 39 is superimposed on the intermediate transfer member 38 to be primary. By being transferred, a color image is formed.
The recording medium P is conveyed to the secondary transfer portion T2 by the conveying means so as to be synchronized with the primary transfer to the intermediate transfer member 38. The conveying means includes a feeding cassette 29 that stores a plurality of recording media P, a feeding roller 30, a separation pad 31, and a registration roller pair 32. At the time of image formation, the feeding roller 30 is driven and rotated in accordance with the image forming operation to separate the recording media P in the feeding cassette 29 one by one, and the registration roller pair 32 performs a secondary operation in synchronization with the image forming operation. It is conveyed to the transfer unit T2.
A movable secondary transfer roller 33 is disposed in the secondary transfer portion T2. The secondary transfer roller 33 can move substantially in the vertical direction. During image transfer, the secondary transfer roller 33 is pressed against the intermediate transfer member 38 via the recording medium P with a predetermined pressure. At the same time, a bias is applied to the secondary transfer roller 33 and the toner image on the intermediate transfer member 38 is transferred to the recording medium P.
Since the intermediate transfer member 38 and the secondary transfer roller 33 are respectively driven, the recording medium P sandwiched between the two is transported at a predetermined transport speed V in the left arrow direction shown in FIG. The belt 34 is conveyed to the fixing unit 35 for the next process. In the fixing unit 35, heat and pressure are applied, and the transferred toner image is fixed on the recording medium P. The recording medium P is discharged onto a discharge tray 37 on the upper surface of the apparatus by a discharge roller pair 36.
4 and 5 are applied to the fixing unit 35 and the secondary transfer roller 33 of the electrophotographic image forming apparatus illustrated in FIG. 6, respectively, so that the image uniformity is excellent. An image forming apparatus capable of providing a high-quality image can be obtained.

Hereinafter, the present invention will be specifically described with reference to examples. In addition, this invention is not limited to a following example.

In this embodiment, the fixing member was manufactured using the following fluororesin and fluoro oil.
(Fluorine resin)
PFA-1: “959HP-Plus” (trade name, manufactured by Mitsui Chemers Fluoro Products)
PFA-2: “451HP-J” (trade name, manufactured by Mitsui Chemers Fluoro Products)
PFA-3: “950HP-Plus” (trade name, manufactured by Mitsui Chemers Fluoro Products)
PFA-4: “P66P” (trade name, manufactured by AGC)
PFA-5: “AW-5000L” (trade name, manufactured by Daikin Industries, Ltd.)
(Fluorine oil)
PFPE-1: “Krytox GPL107” (trade name, manufactured by Chemers)
PFPE-2: “Krytox GPL106” (trade name, manufactured by Chemers)
PFPE-3: “Demnum S200” (trade name, manufactured by Daikin Industries, Ltd.)
PFPE-4: “Krytox 143AD” (trade name, manufactured by Chemers)
PFPE-5: “Krytox VPF16256” (trade name, manufactured by Chemers)
PFPE-6: “Krytox XHT-1000” (trade name, manufactured by Chemers)
PFPE-7: “Fomblin M60” (trade name, manufactured by Solvay)

(Example 1)
(Preparation of preliminary fixing belt)
A base material having an endless belt shape made of nickel electroforming having an inner diameter of 30 mm, a width of 400 mm, and a thickness of 40 μm was prepared as a base layer. Primer treatment was applied to the outer peripheral surface of the substrate.
As a raw material for forming the elastic layer, an addition-curable liquid silicone rubber (trade name: SE1886, manufactured by Toray Dow Corning) containing no filler was prepared. With respect to 61 parts by volume of this liquid silicone rubber, 38 parts by volume of spherical alumina (trade name: Aruna Beads CB-A30S, manufactured by Showa Denko KK) is used as a spherical filler, and vapor grown carbon fiber (trade name: VGCF) is used as a deformed filler. -S, manufactured by Showa Denko KK, aspect ratio = 100, average fiber length = 10 μm) was added by 1 volume part. Thus, an addition-curable silicone rubber composition for forming an elastic layer was prepared. These were applied on the outer peripheral surface of the base material using a ring coating method, and then heated at a temperature of 200 ° C. for 4 hours to crosslink the layer of the addition-curable silicone rubber composition to form an elastic layer having a thickness of 300 μm. Formed.
While rotating the base material on which the elastic layer is formed at a moving speed of 20 mm / sec in the circumferential direction, using an ultraviolet lamp arranged at a distance of 10 mm from the surface of the elastic layer, Ultraviolet rays were irradiated in an air atmosphere. As the ultraviolet lamp, a low-pressure mercury ultraviolet lamp (trade name: GLQ500US / 11, manufactured by Toshiba Lighting & Technology Co., Ltd.) was used, and irradiation was performed so that the integrated light amount at a wavelength of 185 nm on the irradiated surface was 800 mJ / cm ² .
Next, an addition curing type silicone rubber adhesive (trade name: SE1819CV, equal amounts of “A liquid” and “B liquid” manufactured by Toray Dow Corning Co., Ltd.) are mixed on the surface of the elastic layer to a thickness of about 20 μm. It applied so that it might become.
Next, a fluororesin tube (PFA-1, 20 μm thickness, melting point 296 ° C.) having a hydrophilic treatment on the inner surface is covered, and the belt surface is uniformly treated from above the fluororesin tube, so that excess adhesive is removed from the elastic layer. And the fluororesin tube.
Then, in an electric furnace set at a temperature of 200 ° C., put an elastic layer and a base layer coated with a surface layer, heat for 1 hour, cure the adhesive, and bond the fluororesin tube onto the elastic layer, Both ends were cut to obtain a preliminary fixing belt having a width of 343 mm.

(Contact impregnation with fluorine oil)
Perfluoropolyether (PFPE-1) was placed in a borosilicate glass graduated cylinder. A heating wire covered with a heat insulating material was wound around the entire graduated cylinder, and the PFPE temperature was heated to 285 ° C. The prepared preliminary fixing belt was attached to a dipping device, and the entire fixing belt was immersed in heated PFPE. After 5 minutes, the preliminary fixing belt was taken out. Thereafter, the preliminary fixing belt was immersed in a graduated cylinder containing a separately prepared fluorinated solvent (trade name: Novec 7300, manufactured by 3M) to remove excess PFPE adhering to the surface of the fixing belt. After the fluorinated solvent is dried, the fixing belt no. 1 was produced. Fixing belt No. 1 prepared 2 sets in order to use for evaluation mentioned later.
The fixing belt No. The photograph which observed the 1st 1st surface with SEM is shown in FIG. The state in which PFPE aggregated was not observed, suggesting that PFA and PFPE are compatible.

<Evaluation>
Three sets of measurement samples used for Evaluation 1 to Evaluation 3 were prepared as follows.
(Measurement sample preparation)
Fixing belt No. A laminate (diameter 10 mm) of the elastic layer and the surface layer was cut out from 1. Next, the elastic layer is removed from the laminate by immersing the laminate in a silicone resin solubilizer (trade name: eSolve 21RS, manufactured by Kaneko Chemical Co., Ltd.) to dissolve the silicone rubber in the elastic layer. A measurement sample including the entire thickness portion of the surface layer was prepared.

(Evaluation 1: Measurement of fluorine oil adhesion amount P11, P12 and P21)
The measurement sample was cleaned on the first surface opposite to the side facing the base layer. That is, a nonwoven fabric soaked with ethanol was placed on the first surface, and a load of 20 kPa was applied on the nonwoven fabric to reciprocate the position 10 times. Subsequently, the surface was impregnated with toluene and a non-woven fabric was placed thereon, and the position was reciprocated 10 times by applying a load of 20 kPa on the non-woven fabric.
Next, a crystal resonator is placed on the stage part of a tack tester (trade name: TAC-1000, manufactured by Reska Co., Ltd.), while the measurement sample is placed on the probe part of the tack tester, the first surface is It was attached so as to face the crystal unit. Next, the probe was brought close to the stage, and was pressed against the crystal resonator on the first surface of the measurement sample. The pressing conditions are as follows.
・ Pressure: 0.4 MPa,
・ Pressing time: 50 msec,
・ Push-in constant mode,
・ Pressing and lifting speed: 1.0 mm / sec,
Probe set temperature: 180 ° C.
As the crystal resonator, “6A202PN” (trade name, manufactured by Piezo Parts Co., Ltd.) having a fundamental frequency of 6 MHz was used. The frequency characteristics before and after the adhesion were measured by using a QCM-D intermolecular interaction analysis system (Biolin Scientific AB) to measure changes in the series resonance frequency Fs before and after pressing and the frequency Fw representing the loss of vibration energy. From the formula (a), the adhesion amount P11 of fluorine oil per unit area (1 cm ² ) of the crystal resonator was calculated.
Immediately after the pressing process was completed, the measurement sample was removed from the probe, and the first surface was cleaned in the same manner as described above. Next, after placing the measurement sample in an environment of 180 ° C. for 120 seconds, the measurement sample was again attached to the probe and pressed against the crystal resonator under the same pressing conditions as described above. Then, changes in the series resonance frequency Fs and the frequency Fw representing the loss of vibration energy were measured, and the fluorine oil adhesion amount P12 per unit area (1 cm ² ) of the crystal resonator was calculated from the equation (a).

(Evaluation 2: Fluorine oil content in the surface layer)
The first surface and the second surface of another measurement sample were cleaned. Next, the measurement sample was measured under the following conditions using a thermogravimetric analyzer (TGA), and the content ratio (% by mass) of the fluorine oil relative to the surface layer was calculated.
Apparatus: TGA851 (manufactured by METTLER TOLEDO);
Atmosphere: in air;
Temperature: 425 ° C.
In the measurement time-weight loss rate profile obtained by the thermogravimetric analysis described above, a linear least square approximation is obtained from a region where the slope is constant and only PFA is reduced (specifically, after measurement time of 3000 sec). It was. The intercept of the linear least square approximation was defined as the amount of PFA (mass%), and the PFPE content (mass%) = 100−PFA quantity.

(Evaluation 3: Relative ratio of the amount of PFPE on the outermost surface side and the elastic layer side in the thickness direction of the surface layer)
Further, the first surface and the second surface of another measurement sample were cleaned. Next, the measurement sample was measured by the ATR method from the first surface side and the second surface side using an infrared spectrometer (trade name: Frontier MIRNIR, manufactured by PerkinElmer), and the relative ratio of the PFPE amount ( Hereinafter, it is referred to as “PFPE relative amount ratio”).
Specifically, from each of the profile obtained by the infrared spectroscopic analysis, a peak appearing only PFPE (Krytox ^type: 986 cm -1, Demnum ^type: 1010 cm -1, Fomblin type: 1052cm ^-1) the height of the The peak ratio was calculated by dividing by the height of the peak (1146 cm ⁻¹ ) that appears only in PFA. Next, the PFPE relative quantity ratio was calculated by dividing the peak ratio calculated from the measurement result on the second expression side by the peak ratio calculated from the measurement result on the first surface side.

(Evaluation 4: Evaluation of presence or absence of toner offset)
Fixing belt No. No. 1 was attached to an electrophotographic image forming apparatus (trade name: imageRUNNER-ADVANCE C5051; manufactured by Canon Inc.) having an adjusted angle of paper separation claws.
Then, an image forming process for forming a 10 cm × 10 cm cyan solid image on A4 size paper (International Paper, basis weight 75 g / m ² ) was performed. The fixing temperature was 180 ° C., and the paper conveyance speed was 300 mm / sec.
At each point when the number of cyan solid images reached 1, 100 and 100,000, A4 size plain paper thin paper (trade name: CS-520, basis weight 52 g / m ² , Canon 1 sheet), and a cyan solid image of 10 cm × 10 cm was formed. The solid image formed on this plain paper thin paper was observed visually and with a microscope and evaluated according to the following criteria.
(Evaluation criteria)
Rank A: There is neither toner offset nor toner missing.
Rank B: A small amount of toner offset and toner missing are confirmed. Rank C: Both toner offset and toner missing are confirmed.
Rank D: Plain thin paper stuck to the fixing belt.

(Evaluation 5: Measurement of surface free energy)
In Evaluation 4, the fixing belt No. immediately before solid image formation on plain thin paper was measured. The surface free energy of the outer surface of 1 was calculated by the “Kitazaki-Hatabe method” described in Non-Patent Document 1. Specifically, the fixing belt No. The contact angle of water, n-hexadecane, and diiodomethane was measured on the outer surface of 1 (measurement environment: temperature 23 ° C., relative humidity 55%).
Next, using the measurement results of each contact angle, according to the description in “2. Expansion of Forks formula” to “3. Surface tension and components of polymer solid” on page 131 of Non-Patent Document 1, “Expanded Fowkes” Surface free energy was calculated from
A contact angle meter (trade name: DM-501, manufactured by Kyowa Interface Science Co., Ltd.) was used for contact angle measurement, and an analysis software (product name: FAMAS, manufactured by Kyowa Interface Science Co., Ltd.) was used for surface free energy analysis. .

(Examples 2 to 18)
In the same manner as in Example 1 except that the fluororesin type used in the surface layer, the fluoro oil type, and the fluoro oil temperature at the time of contact are changed as shown in Table 2, the fixing belt No. 2 to 18 were produced.

(Example 19)
In Example 1, the fixing belt No. 1 was changed in the same manner as in Example 1 except that the contact time between the fixing member and the fluorine oil was 1 minute. 19 was prepared and used for Evaluation 1 to Evaluation 5.

(Example 20)
In Example 1, a solution obtained by diluting PFPE with a fluorine-based solvent (trade name: Novec 7300, manufactured by 3M) was spray-coated on the surface of the fixing member, and then put into a drying furnace and heated at 285 ° C. for 5 minutes. In the same manner as in Example 1, the fixing belt No. 20 was produced.

(Comparative Example 1)
A preliminary fixing belt was prepared by the method described in Example 1, and this was used as a fixing belt No. 1 according to this comparative example. C-1.

(Comparative Example 2)
Fixing belt No. Sodium naphthalene (trade name: Tetra Etch, manufactured by Junko Co., Ltd.) was applied to the outer surface of C-1, and the outer surface was chemically hydrophilized.
Next, PFPE (trade name: Optool DSX, manufactured by Daikin Industries, Ltd.) whose molecular terminals were modified with alkoxysilane was dissolved in a fluorine-based solvent (trade name: Novec 7300, manufactured by 3M). The solution was applied to the hydrophilized outer surface and then baked in a drying furnace heated to 120 ° C. for 1 hour to chemically fix PFPE. Thereafter, the outer surface on which the PFPE was chemically fixed was washed with the above-mentioned fluorinated solvent. C-2 was produced.

(Comparative Example 3)
The fixing belt No. 1 was changed in the same manner as in Example 1 except that the temperature of the fluorine oil brought into contact with the outer surface of the preliminary fixing belt was 210 ° C. C-3 was produced.
(Comparative Example 4)
A base layer and an elastic layer were produced by the method described in Example 1. After the surface of the elastic layer was treated with excimer UV, a primer (trade name: EK-1909S21L, manufactured by Daikin Industries, Ltd.) was spray-coated uniformly to a thickness of 2 μm and dried.
Next, two spray guns were prepared. One spray gun was filled with an aqueous dispersion paint of PFA particles (trade name: AW-5000 L, manufactured by Daikin Industries, Ltd., melting point 300 ° C.). The other spray gun was filled with a solution in which PFPE-1 was dissolved in a fluorine-based solvent (trade name: Novec 7300, manufactured by 3M). And using these spray guns, the aqueous dispersion paint of PFA and PFPE were apply | coated to the surface of an elastic layer, and the 20-micrometer-thick coating film containing a PFA particle and PFPE was formed. At this time, the amount of spray gun applied was adjusted so that the content of PFPE-1 in the coating film was 2.0 wt%.
Next, the coating film was heated at a temperature of 350 ° C. for 15 minutes to melt the PFA particles in the coating film to form a surface layer. C-4 was obtained. The photograph which observed the outermost surface side of the surface layer with SEM is shown in FIG. It can be seen that PFPE is agglomerated and PFA and PFPE are not compatible.
Fixing belt No. 2 to 20 and fixing belt No. C-1 to C-4 were subjected to Evaluation 1 to Evaluation 5. Fixing belt No. 1 to 20 and fixing belt No. The evaluation results of C-1 to C-4 are shown in Tables 2 to 3.

Table 3 shows the results obtained by subjecting the fixing members produced in Examples 1 to 20 and Comparative Examples 1 to 4 to Evaluations 1 and 2.

From Table 3, it was found that the fixing member according to this embodiment can maintain excellent toner releasability even after long-term use, and as a result, a high-quality electrophotographic image can be formed.

The present invention is not limited to the above embodiment, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, in order to make the scope of the present invention public, the following claims are attached.

The present application is Japanese Patent Application Japanese Patent Application No. 2018-055190 filed on March 22, 2018, Japanese Patent Application Japanese Patent Application No. 2018-055191 filed on March 22, 2018, and Japanese Patent Application filed on February 20, 2019. Claiming priority based on Japanese Patent Application No. 2019-028564, Japanese Patent Application No. 2019-028560 filed on Feb. 20, 2019 and Japanese Patent Application No. 2019-031637 filed on Feb. 25, 2019 The entire contents of which are incorporated herein by reference.

11 Fixing belt 12 Fixing roller 13 Base layer 14 Elastic layer 15 Surface layer

Claims

A fixing member for electrophotography having a base layer, an elastic layer, and a surface layer on the elastic layer in this order in the thickness direction,
The elastic layer comprises silicone rubber;
The surface layer consists of a single layer;
The surface layer includes a fluororesin and a fluoro oil having a perfluoropolyether structure, and the fixing member satisfies the requirements (i) and (ii):
(I) For a measurement sample including the entire thickness portion of the surface layer collected from the fixing member, after cleaning a predetermined position on the first surface opposite to the side facing the base layer, A unit area of the detection surface when a process of pressing the detection surface of the quartz crystal microbalance (QCM) sensor at a temperature of 180 ° C. for 50 msec with respect to the position is performed. The mass P11 of the deposit containing the fluorine oil having a perfluoropolyether structure attached to (1 cm 2 ) is 1.0 × 10 2 ng or more and 1.0 × 10 4 ng or less;
(Ii) For the measurement sample subjected to the treatment specified in the requirement (i), after cleaning the position, the sample is placed in an environment at a temperature of 180 ° C. for 120 seconds, and then a quartz crystal microbalance (QCM) is placed at the position. ) A perfluoropolyether structure adhering to the unit area (1 cm 2 ) of the detection surface when the detection surface of the sensor is pressed at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. The mass P12 of the deposit containing fluorine oil is 0.5 × P11 or more and 1.2 × P11 or less.
A fixing member for electrophotography having a base layer, an elastic layer, and a surface layer on the elastic layer in this order in the thickness direction,
The elastic layer comprises silicone rubber;
The surface layer consists of a single layer;
The surface layer includes a fluororesin and a fluoro oil having a perfluoropolyether structure,
A quartz crystal microbalance (QCM) sensor with respect to the first surface opposite to the side facing the base layer of the measurement sample including the entire thickness portion of the surface layer collected from the fixing member And a fluorine oil having a perfluoropolyether structure that adheres to a unit area (1 cm 2 ) of the detection surface when the detection surface is pressed at a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. The mass of the kimono is P11 (ng),
With respect to the second surface of the measurement sample facing the base layer, the detection surface of the quartz crystal microbalance (QCM) sensor is set to a pressure of 0.4 MPa at a temperature of 180 ° C. for 50 msec. P21> P11, where P21 (ng) is the mass of the deposit containing fluorine oil having a perfluoropolyether structure that adheres to the unit area (1 cm 2 ) of the detection surface when pressed. A fixing member.
The fixing member according to claim 1 or 2, wherein the content of the fluorine oil in the surface layer is 1.0% by mass or more and 25% by mass or less of the surface layer.
The fixing member according to claim 1, wherein the P11 is 1.0 × 10 2 ng or more and 5.0 × 10 3 ng or less.
The fixing member according to any one of claims 1 to 4, wherein the fluororesin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA).
The fixing member according to claim 1, wherein the thickness of the surface layer is 5.0 μm or more and 50 μm or less.
The fixing member according to any one of claims 1 to 6, wherein the fluorine oil is perfluoropolyether.
The fixing member according to any one of claims 1 to 7, wherein the perfluoropolyether has a chemical structure represented by a structural formula (1).

(In Structural Formula (1), a, b, c, d, e, and f are each independently 0 or a positive integer, satisfying 1 ≦ a + b + c + d + e + f ≦ 600, and a, b, c, and d At least one represents a positive integer.)
The fixing member according to any one of claims 1 to 8, wherein the perfluoropolyether has at least one chemical structure selected from the group consisting of structural formulas (2) to (4).

(In Structural Formulas (2) to (4), m and n each independently represents an integer of 1 or more).
The perfluoropolyether has a chemical structure of the formula (3), the P11 is 1.0 × 10 2 ng or more and 5.0 × 10 3 ng or less, and the perfluoropolyether in the surface layer The fixing member according to claim 9, wherein the content of is 1.0% by mass or more and 25% by mass or less of the surface layer.
The fixing member according to any one of claims 1 to 10, wherein the fixing member is a fixing belt having an endless belt shape.
A fixing device comprising: the fixing member according to any one of claims 1 to 10; and heating means for the fixing member.
13. The fixing device according to claim 12, wherein the fixing member is a fixing belt having an endless belt shape, and the heating means is a heater disposed in contact with an inner peripheral surface of the fixing belt.
An electrophotographic image forming apparatus comprising the fixing device according to claim 12.